Performance Characteristics Detection Limit : 0.4 pmol/L ; Linear Range: 0.4~50.0 pmol/L; Linear correlation coefficient R ≥ 0.990; Precision: within batch C.V. is ≤ 15%; between batches C.V. is ≤ 20%; Accuracy: the relative deviation of the measurement results shall not exceed ± 15% when the accuracy calibrator prepared by FT3 national standard or standardized accuracy calibrator are tested. Cross-Reactivity:The following substances do not interfere with the T4 test results at the indicated concentrations: TT4 at 500ng/mL,rT3 at 50ng/mL. 1. Store Aehealth FT3 Rapid Quantitative test cassette at 2～30℃, shelf life is up to 18 months. 2. Test cassette should be used within 1 hour after opening the pack. 3. test cassette should be used within 1 hour after opening the pack. The determination of serum or plasma levels of Triiodothyronine (T3) is recognized as an important measurement in the assessment of thyroid function. Its effects on target tissues are roughly four times more potent than those of T4. Free T3 (FT3) is the unbound and biologically active form, which represents only 0.2‐0.4 % of the total T3. The determination of free T3 has the advantage of being independent of changes in the concentrations and binding properties of the binding proteins; Therefore free T3 is a useful tool in clinical routine diagnostics for the assessment of the thyroid status. Free T3 measurements support the differential diagnosis of thyroid disorders, are needed to distinguish different forms of hyperthyroidism, and to identify patients with T3 thyrotoxicosis.